Oh by the way John pre war the Hilfspolitzei role was usualy taken by SA members who wore there own uniform and headgear.
Just about the rarest shako in my view is the white summer one i believe usualy worn by the traffic police ive seen a few pictures but never seen one in the flesh.

May the fleas of a thousand camels infest the crotch of the person who screws up your day and may their arms be too short to scratch.

A good repro solution should be to catch a "Maschinengewehr Abteilung" Tschako vom Georg Dehn wihout the imperial insigna and to put Eagle and third reich insignas on it. Price of such piece schould be about 250€. Other solution is to make Fiber glass copy and to paint it properly.